Loud speaker



Oct. 31, 1933. H R V b v 1,932,461

LOU D SPEAKER Filed June 7, 19s2 2 sheets-sheet 1 INVENTOR Oct. 31,1933. H. R. VAN DEVENTER LOUD SPEAKER.

Filed June 7, 1932 2 Sheets-Sheet 2 INVENTOR m Potent ed @ct. 31, 1933 LGIUED SPEAKlEl-Rt ifilarry llhllan Deventer, New ilorh, i i. 52,, us-

signor to ii'atcnt Engineering @orporction, a corporation or Delaware fill l liwtfion June 7, 19323. Serinl No. iiliiiifiii (Claims,

- merits one of which is adapted not only to impart its motion to u diaphragm, but is also adapted to transmit motion from the other element to the diaphragm.

it further object oi the invention is to provide a loud spealreriin which vibrations of the lower register in one element are superimposed upon on element vibrating in the intermediate and lower registers, endln which a diaphragm ettached to one of the vibrating elements receives the vibrations oi both elements.

Other objects and advantages of the invention will be apparent to those skilled in the art from A the description of one embodiment thereof herein.

it is well known in the art that some types oi loud speakers, for example the dynamic types, ieithiully reproduce tones of middle and lower register of the audible range, while other types of speakers, tor example the piezo-electric crystal types, faithfully reproduce tones oi the middle and high register.

The present invention contemplates the use of two types of reproducers, which together faithfully reproduce ell or the tones oil the audible range, combined in as novel monner wherein one oi the reproducers to the connecting lint; be tween the other reproducer and a suitable din= phregm, and not only transmits impulses from the other reproducer to the disphrbut also re-= produces and imparts impulses thereto.

in a preferred embodiment of the invention as illustrated in the drawings:

Figure l is a sectional elevation showing the relation oi the two reproducers to the diaphra 1m A frame 10 is provided and acts as a main support for the other elements. Aciroular o ii in the frame 1o hos the core l2 concentric therewith, with a space between the core 12 and the inner surface of the opening ll. The core 12 has an electro-magnetic winding 13 thereon and is held in concentric relation to the opening ill by myohe i l which is secured. tothe frame it in any suitable manner, the core 12 being securely fastened to the yoke it.

When the winding it is energized, magnetic lines oi force build up in the core l2 end the core 12, the yolre l4 and a portion or the irnme lo form n peth for the magnetic fl thereby en intense metic held in the annular space between the sources oi the opening ll end the m core 12 is produced,

A movable coil is is positioned in this ennuler space end is adapted to receive currents from o, suiteble source, iorexemple the" modulated out= put of an amplifier, and to move in time relation 9 to these currents due to the presence of this mov= able coil in the intense ileld between the open= ll end the core 12.

in the present speakers oi this character, celled in the trade electro-dynumic speolrers, it is customary to mount the movable coil directly on the apex of n cone shaped diaphragm. in the improved loud speaker described herein the movebie coil is is secured to the movable arm 16 oie, crystal reproducer ll. A second erm it or the reproducer i7 is secured to the open it of n diaphragm or cone 20. The crystnl reproducer is secured to the irame it by means of brackets 23 end 24' which are in 11:11 secured to clump members 21 end 22 respectively. These clamp members support the crystal on opposite sides thereoi end the arm it before mentioned is extended from the clp 2i and the erm it is on extension of the clp 22. The crystal has electrodes one of which is site at 25 in Pics 2 and 4 with s, lend wire 26 connected thereto to when these electrodes are connected to a suitable amplifier the crystal 1'? flexes as indiceted by the arrows 27, the solid arrow showing one movement and the dotted arrow showing the opposite movement. it the dynamic portion of the speaker were not cone. nected the motion 01 the crystal 1'? would beimparted to the cone 20 via the arm 18.

An annular ring 3'i of L cross section is sup- ,1 ported by the frame 10, and the outer edge 33' or the cone ,20 is clamped between the ring 37 and an outer clamp ring 39, the clamping being effected by means of screws 40 and bolts 41. The screws 40 also serve for securing the cone spams, bly to the frame 10. 1

Wit

- movahle coil adjacent to said magnet, or element carried by said frame, cone sin, U

' A felt ring 42 is providedfor membering up against a suitable baiile board (not shown).

Both reproducers are cdnnected as shown in Figure 4 in which 28 and 29 represent terminals of any suitable source of modulated impulses, for example an amplifier, and the primary 33 of the transformer 32 is connected in parallel with the terminals 28 and 29 via the wires 30 and 31 respectively. The secondary 34 of the transformer'32 is connected to the moving coil 15.

The magnet winding 13 is connected via the terminals 35 and 36 to a suitable source of direct current.

One of the crystal electrodes is connected via the wires 26 and 30 to the terminal 28 and the other crystal electrode is connected via the wires 26a and 31 to the terminal 29.

With the device connected up as shown in Figure 4 to the amplifier or a radio set which is receiving a broadcast, the tones of the middle and lower ranges of frequency are more faithfully reproduced by the electro-dynamic portion of the speaker and these tones are carried to the cone 20 via the arm 16, the crystal element 1'? and the arm 18. At the same time tones of the higher ranges are more favorably reproduced by the crystal element and they are imparted via the arm 18 to the cone 20, resulting in faithful reproduction of all tones of the audible range.

Many changes may be made in this device by those skilled in the art without departing from the invention herein described and illustrated, and as defined in the following claims.

What is claimed is:

1. In a loud speaker, an electro-dynamic reproducer having a moving element, a or stai re producer, a diaphragm, an arm connected to said crystal adapted to support said moving element, and a second arm secured to said crystal and adapted to move said diaphragm.

2. in a device of the character descrihed, a irame, electro-magnet secured to a movahlc coil adjacent to said magnet, crystal element a, ried by said frame, diaphragm s crystal to 3., in device or the cha ter des frame, an electro magnet secured ta said 1,932,4ldil on said frame having its apex adjacent to said crystal, an arm secured to said crystal and to said movable coil, and a second arm secured to said crystal and to the apex of said cone.

s. In a device of the character described, a

frame having a circular opening therein, a yoke secured'to said frame, a core carried by said yoke extending into said opening and positioned substantially concentric therewith forming therebetween an annular air gap, an electro-magnetic winding on said core for producing a magnetic field, a-crystal reproducing element mounted on said frame, a diaphragm also supported by the frame, an arm secured to said crystal and adapted to support a movable coil in said air gap, and a second arm secured to said crystal and adapted to move said diaphragm.

5. In a-loud speaker, an electro-dynamic reproducing element having a supporting frame, a diaphragm supported by said frame, a piezo-electric crystal having clamping members on opposite sides thereof, a bracket secured to each of said clamping members and adapted to support said crystal on said frame, an arm extending from one of said clamps to a movable member of said dynamic reproducing element, and an arm o tending from the other or said clamps operatively connected to said diaphragm.

6. In a loud speaker, an electro-dynamic reproducing element having a supporting frame, a cone supported by said frame and having an apex extending from said element, a crystal reproducing element having clamping members on opposite sides thereof, a bracket secured to each of said clamping members and adapted to support said crystal on said frame, an arm extending from one of said clamps to a movable member or said dynamic reproducing element, and an arm era" tending from the other off said clamps SECEE-l'fid to the apex of cone.

i. In a device of the character descrihed, eiectro-magnetic held, a source of direct current therefor, a transformer, movable coil connected the secon y of said transformer, a crystal electrodes, a 5 connected to a pr to said also Tiliii italic 

